Month-specific sea-surface temperature · Bonaire

Klein Bonaire Sea Temperature in September

29.7°C

85.5°F

In September, sea-surface temperature near Klein Bonaire has a historical monthly average of 29.7°C. This is not the reading for any particular holiday date.

Across 2023–2025, the lowest and highest yearly September monthly means were 29.2–30.0°C. These are not daily extremes.

Previous month

August · 29.0°C

Change into September: +0.7°C

Next month

October · 30.1°C

Change into next month: +0.4°C

Can you swim or snorkel in Klein Bonaire in September?

At 29.7°C our temperature-only guide describes the water as very warm water. Comfort depends on your cold tolerance, immersion time and wind. A historical average cannot determine whether conditions are safe on any given day.

Do you need a wetsuit?

Swimwear is usually enough; a rash guard adds sun protection.

Which beach should you choose?

Look for a beach sheltered from the actual forecast waves and wind on your visit. Exposure, currents and entry conditions vary even where water temperatures are similar. Follow local warnings.

Check the current waves, wind and snorkeling forecast →

A live forecast does not predict a future September. Check again close to your trip.

Waves and wind: recorded-model conditions for September

These figures come from a separately modelled, date-specific wind/wave backfill, not the NOAA SST series. A single observed season is not a climatological likelihood or a guarantee of safe conditions.

Compare nearby coasts with their own evidence

Coast	Morning	Afternoon	Period
Kralendijk	0%	0%	Sep 2026

A “calm hour” meets fixed modelled wave/wind thresholds; neither visibility nor local currents, entry conditions or actual beach safety is measured here. Periods may differ by coast.

Klein Bonaire Sea Temperature: All 12 Months

Choose a month for available historical evidence, month comparisons and swim guidance. Missing history is clearly marked and never presented as a long-term normal.

January 27.6°C February 26.9°C March 27.0°C April 27.4°C May 28.0°C June 28.3°C July 28.5°C August 29.0°C September 29.7°C October 30.1°C November 29.3°C December 28.3°C

Data source and limitations

Source: Open-Meteo Marine API, MeteoFrance sea-surface temperature; 2023–2025. Marine model grid near 12.15, -68.28. Based on 3 yearly monthly means and 2160 recorded samples. Source methodology.

Modelled sea-surface temperatures do not establish underwater visibility, wildlife, calm currents or safe entry.